I picked up a S&W M3000 shotgun with RIS (spring, clear bodied, black clip/handle/pump).
It has adjustable hop up and uses a clip, so you can pound out 19 or so rounds quickly. You can also hold the trigger down and auto-pump-fire it.
It was like $30 with a speed loader tube. It's okay for accuracy and feels solid. So if you just want one for casual plinking, I'd check it out. Cost me around $35-$40.